A method and system for identifying a failure of a wind turbine group variable pitch control requirement

Abstract

The present application belongs to the technical field of wind turbine variable pitch control, and particularly relates to a method for identifying failure of wind turbine variable pitch control demand, which obtains a comparison threshold value through processing of a second input parameter, and if a first input parameter is greater than the comparison threshold value, then the size of a small-pitch-angle overspeed rotation speed pitch angle threshold value and a current variable pitch demand average angle is determined, and if the small-pitch-angle overspeed rotation speed pitch angle threshold value is greater than the current variable pitch demand average angle, then time accumulation is started to obtain a time accumulation value. The accumulated time is used to determine whether the failure of the wind turbine variable pitch control demand is a transient state or a long-time state. If it is determined that the failure is a non-transient state, it is indicated that the variable pitch control demand is failed, and a protection operation is performed to ensure normal and safe operation of the unit.

Description

Technical Field

[0001] This invention belongs to the field of wind turbine pitch control technology, specifically relating to a method and system for identifying the failure of pitch control requirements in wind turbine generator sets. Background Technology

[0002] A horizontal axis wind turbine's rotor absorbs wind energy and rotates, which in turn drives a connected generator to generate electricity. The control objectives of a wind turbine vary depending on the wind speed. Above the rated wind speed, the control objective is to use pitch control to keep the turbine's speed near the rated speed, thereby ensuring that the turbine's output power is close to the rated power and that the mechanical and electrical components of the wind turbine operate normally within their design range.

[0003] Traditional generator speed-pitch control loops use the difference between the actual detected generator speed and the setpoint as the control input. This difference is then used to provide the corresponding pitch angle via PI or PID control. The pitch angle limits or absorbs wind energy to control the generator speed. While this traditional loop is closed-loop, the process from issuing the pitch control command to the execution by the pitch actuator, and finally to the entire wind turbine controlling the generator speed due to pitch action limiting or releasing wind energy, presents a challenge. Since the wind turbine rotor is a large inertial component, there is a time lag between the pitch control command and the actual generator speed control target being achieved. This leads to a mismatch between the required pitch angle and the generator speed. For example, a larger pitch angle might be needed to adjust for larger speed fluctuations, but the given pitch control command might be too small to address these fluctuations. Without intervention, the generator speed control target cannot be achieved. Summary of the Invention

[0004] The purpose of this invention is to provide a method for identifying the failure of pitch control requirements of wind turbine generator sets, and to address the problem in the prior art that it is impossible to analyze the matching between pitch control requirements and generator speed, thereby providing a more targeted solution to the problem of not being able to identify the failure of pitch control requirements of wind turbine generator sets.

[0005] This invention is achieved through the following technical solution:

[0006] A method for identifying failures in the pitch control requirements of wind turbine generators, specifically including the following steps:

[0007] S1. Obtain the first input parameter and the second input parameter;

[0008] The comparison threshold is obtained by preprocessing the second input parameter.

[0009] If the first input parameter is less than or equal to the comparison threshold, the control flow ends.

[0010] If the first input parameter is greater than the comparison threshold, start S2;

[0011] S2. Obtain the small pitch angle overspeed speed pitch angle threshold and the blade pitch requirement command;

[0012] The average angle of the current pitch requirement is obtained based on the blade pitch requirement command.

[0013] If the small pitch angle overspeed speed pitch angle threshold is greater than the current average pitch angle requirement, then time accumulation begins to obtain the accumulated time value.

[0014] S3. Obtain the threshold for holding the speed overrun time at small pitch angle;

[0015] Determine whether the cumulative time value is greater than the threshold for holding the speed overrun time at small pitch angle;

[0016] If the cumulative time value is less than or equal to the threshold value for holding the overspeed speed at the small pitch angle, the control process terminates.

[0017] If the cumulative time value is greater than the threshold value for holding the speed overspeed at the small pitch angle, it indicates that the pitch control requirement of the wind turbine generator set has failed, and the pitch system will perform a protection operation.

[0018] Furthermore, when the first input parameter is the generator speed, the second input parameter is the current rated speed of the generator;

[0019] S1 specifically refers to:

[0020] 1.1. Obtain the current generator speed and the current rated generator speed;

[0021] 1.2 Multiply the current generator rated speed by the small pitch angle overspeed gain coefficient to obtain the small pitch angle overspeed judgment value omega_rated*factor_spo;

[0022] 1.3. Determine whether the current generator speed is greater than the overspeed judgment value omega_rated*factor_spo for small pitch angle;

[0023] If the current generator speed is less than or equal to the small pitch angle overspeed judgment value omega_rated*factor_spo, the control process ends;

[0024] If the current generator speed is greater than the speed judgment value of small pitch angle overspeed omega_rated*factor_spo, time accumulation begins and the accumulated time value is obtained.

[0025] Furthermore, when the obtained blade pitch demand command is a three-blade pitch demand command, in S2, the current pitch demand angles of the three blades are averaged to obtain the average current pitch demand angle of the three blades.

[0026] Determine whether the average angle of the current pitch requirement of the three blades is less than the small pitch angle overspeed speed pitch angle threshold.

[0027] If the pitch angle threshold is less than or equal to the average angle of the current pitch requirement of the three blades, the control process will terminate.

[0028] If the small pitch angle overspeed speed pitch angle threshold is greater than the average angle of the current pitch requirement of the three blades, time accumulation begins to obtain the accumulated time value.

[0029] Furthermore, the current pitch requirement angles of the three blades are averaged to obtain the average current pitch requirement angle of the three blades. The specific process is as follows:

[0030] The summation of the current pitch adjustment angles of the three blades is expressed as follows:

[0031] pitch_demand_sum=pitch_demand1+pitch_demand2+pitch_demand3;

[0032] Where 1pitch_demand1 is the current pitch demand angle for the first blade; pitch_demand2 is the current pitch demand angle for the second blade; and 3pitch_demand3 is the current pitch demand angle for the third blade.

[0033] Divide pitch_demand_sum by 3 to get the average pitch demand angle for the three-bladed pitch.

[0034] Furthermore, when the obtained blade pitch demand command is a single blade pitch demand command, in S2, it is determined whether the current pitch demand angle of a certain blade is less than the small pitch angle overspeed speed pitch angle threshold.

[0035] If the small pitch angle overspeed speed pitch angle threshold is less than or equal to the average angle of the current pitch requirement of a certain blade, the control process terminates.

[0036] If the small pitch angle overspeed speed pitch angle threshold is greater than the average angle required for the current pitch of a certain blade, then time accumulation begins to obtain the accumulated time value.

[0037] Furthermore, in S3, the pitch system performs protection operations in the form of shutdown, power limiting, or speed limiting.

[0038] Furthermore, when the pitch system performs a shutdown operation using the shutdown method, the specific steps are as follows:

[0039] The pitch control system retracts the pitch to its final position according to the pitch rate requirement, and the generator torque is given by looking up the generator speed in a table.

[0040] Furthermore, when the pitch system performs a shutdown operation using a power-limiting method, the power setpoint is set to 50%-80% of the rated power, and the pitch control circuit and torque control circuit operate with limited power according to this power setpoint.

[0041] Furthermore, when the pitch system performs a shutdown operation using a speed-limited method, the speed setpoint is set to 70%-90% of the rated speed, and the pitch control loop operates at the speed-limited value according to this speed setpoint.

[0042] A system for identifying failures in the pitch control requirements of wind turbine generators, specifically comprising:

[0043] The acquisition module is used to acquire the first input parameter, the second input parameter, the small pitch angle overspeed speed hold-up threshold, and the blade pitch requirement command;

[0044] The preprocessing module is used to preprocess the second input parameter to obtain the comparison threshold;

[0045] The first comparison module is used to compare the first input parameter with the comparison threshold;

[0046] If the first input parameter is less than or equal to the comparison threshold, the control flow ends.

[0047] If the first input parameter is greater than the comparison threshold, then the second comparison module is activated;

[0048] The calculation module is used to obtain the average angle of the current pitch requirement based on the blade pitch requirement command.

[0049] The second comparison module is used to determine the magnitude of the small pitch angle overspeed speed pitch angle threshold and the average angle of the current pitch requirement.

[0050] If the small pitch angle overspeed speed pitch angle threshold is greater than the current average pitch angle requirement, then the time accumulation module is activated.

[0051] The time accumulation module is used to accumulate time and obtain the accumulated time value;

[0052] The third comparison module is used to determine whether the cumulative time value is greater than the threshold for holding the speed overspeed time at small pitch angle.

[0053] If the cumulative time value is less than or equal to the threshold value for holding the overspeed speed at the small pitch angle, the control process terminates.

[0054] If the cumulative time value is greater than the threshold value for holding the speed overspeed at the small pitch angle, it indicates that the pitch control requirement of the wind turbine generator set has failed, and the pitch system will perform a protection operation.

[0055] Compared with the prior art, the present invention has the following beneficial technical effects:

[0056] This invention discloses a method for identifying pitch control failures in wind turbine generators. A comparison threshold is obtained by processing a second input parameter. If the first input parameter is greater than the comparison threshold, the method begins to compare the small pitch angle overspeed speed pitch angle threshold with the current average pitch requirement angle. If the small pitch angle overspeed speed pitch angle threshold is greater than the current average pitch requirement angle, time accumulation begins to obtain the accumulated time value. The accumulated time is used to determine whether the pitch control failure is instantaneous or prolonged. If it is determined to be non-instantaneous, indicating a pitch control failure, a protection operation is performed to ensure the normal and safe operation of the generator.

[0057] The pitch control demand command is used as the conditional input to identify whether the pitch control demand of the wind turbine generator has failed, without the need for additional detection hardware; when the pitch control demand failure is detected, the shutdown protection is immediately implemented to prevent the control target from failing due to erroneous pitch control demand.

[0058] Furthermore, if the generator speed continues to rise, and the pitch control command is still too low, causing the speed to continue to rise, it can lead to serious consequences such as overspeeding. Therefore, this invention uses the generator speed as the condition input for identifying whether the pitch control requirement of the wind turbine generator set has failed. When the generator speed exceeds the comparison threshold, time accumulation begins. When the accumulated time is greater than the small pitch angle overspeed speed time maintenance threshold, it is determined to be a failure and immediate shutdown protection is required. Attached Figure Description

[0059] Figure 1 This is a flowchart of Embodiment 1 of the present invention. Detailed Implementation

[0060] To make the objectives, technical solutions, and advantages of the present invention clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention; that is, the described embodiments are only a part of the embodiments of the present invention, and not all of them.

[0061] The components described and illustrated in the accompanying drawings and embodiments of this invention can be arranged and designed in various different configurations. Therefore, the detailed description of the embodiments of the invention provided in the following drawings is not intended to limit the scope of the claimed invention, but merely to illustrate one selected embodiment of the invention. All other embodiments obtained by those skilled in the art based on the accompanying drawings and embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0062] It should be noted that the terms “comprising,” “including,” or any other variations are intended to cover non-exclusive inclusion, such that a process, element, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to the process, element, method, article, or apparatus.

[0063] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0064] Example 1

[0065] like Figure 1 As shown, this invention discloses a method for identifying the failure of pitch control requirements in wind turbine generator sets, specifically including the following process:

[0066] 1. Obtain the current generator rated speed omega_rated; obtain the overspeed speed gain coefficient factor_spo at small pitch angle;

[0067] 2. Multiply the current generator rated speed omega_rated by the small pitch angle overspeed speed gain coefficient factor_spo to obtain omega_rated*factor_spo, which is called the small pitch angle overspeed speed judgment value.

[0068] 3. Obtain the current generator speed (omega);

[0069] 4. Determine if the current generator speed omega is greater than omega_rated * factor_spo;

[0070] If the current generator speed omega is less than or equal to omega_rated * factor_spo, the control flow ends.

[0071] 5. If the current generator speed omega is greater than omega_rated*factor_spo, then obtain the small pitch angle overspeed speed pitch angle threshold and the current pitch requirement angle of the three blades.

[0072] The summation of the current pitch requirement angles of the three blades yields:

[0073] pitch_demand_sum=pitch_demand1+pitch_demand2+pitch_demand3;

[0074] Where 1pitch_demand1 is the current pitch demand angle of the first blade; pitch_demand2 is the current pitch demand angle of the second blade; 3pitch_demand3 is the current pitch demand angle of the third blade; divide pitch_demand_sum by 3 to get the average pitch demand angle of the three blades, pitch_demand_avg.

[0075] 6. Determine the relationship between the small pitch angle overspeed speed pitch angle threshold and the average angle required by the current pitch control of the three blades;

[0076] If the speed of the small pitch angle exceeds the pitch angle threshold, which is greater than the average angle required for the current pitch control, then the timer will start accumulating time. The timer is initially set to 0 and the time is accumulated.

[0077] 7. Obtain the time-hold threshold for small pitch angle overspeed rotational speed;

[0078] Determine if the timer is greater than the durationthreshold_spo;

[0079] If timer is less than or equal to durationthreshold_spo, the control flow terminates;

[0080] If the timer is greater than the durationthreshold_spo, the pitch system will perform a shutdown operation;

[0081] The pitch system performs a shutdown operation as follows: the pitch system uses pitchrate_demand to provide the pitch rate requirement and retracts the pitch to the final position; the generator torque is given by the generator speed lookup table using the generator torque command torque_demand.

[0082] Example 2

[0083] like Figure 1 As shown, this invention discloses a method for identifying the failure of pitch control requirements in wind turbine generator sets, specifically including the following process:

[0084] 1. Obtain the current generator rated speed omega_rated; obtain the overspeed speed gain coefficient factor_spo at small pitch angle;

[0085] 2. Multiply the current generator rated speed omega_rated by the small pitch angle overspeed speed gain coefficient factor_spo to obtain omega_rated*factor_spo, which is called the small pitch angle overspeed speed judgment value.

[0086] 3. Obtain the current generator speed (omega);

[0087] 4. Determine if the current generator speed omega is greater than omega_rated * factor_spo;

[0088] If the current generator speed omega is less than or equal to omega_rated * factor_spo, the control flow ends.

[0089] 5. If the current generator speed omega is greater than omega_rated*factor_spo, then obtain the small pitch angle overspeed speed pitch angle threshold pitch angle_spo, and the current pitch requirement angle of a single blade.

[0090] 6. Determine whether the current pitch angle required for a single blade is less than the pitch angle overspeed speed threshold pitch angle_spo;

[0091] If the current pitch requirement angle of a single blade is greater than or equal to the pitch angle overspeed speed pitch angle threshold pitchthreshold_spo, the control flow terminates.

[0092] If the current pitch requirement angle of a single blade is less than the pitch angle overspeed speed pitch angle threshold pitchthreshold_spo, the time accumulation timer is started. The timer is initially set to 0 and the time is accumulated.

[0093] 7. Obtain the time-hold threshold for small pitch angle overspeed rotational speed;

[0094] Determine if the timer is greater than the durationthreshold_spo;

[0095] If timer is less than or equal to durationthreshold_spo, the control flow terminates;

[0096] If the timer is greater than the durationthreshold_spo, the pitch system will perform a shutdown operation;

[0097] The pitch system performs a shutdown operation as follows: the pitch system uses pitchrate_demand to provide the pitch rate requirement and retracts the pitch to the final position; the generator torque is given by the generator speed lookup table using the generator torque command torque_demand.

[0098] This invention uses generator speed and pitch control commands as control inputs, and determines whether the generator speed and pitch control commands match by judging their relationship with a threshold.

[0099] This invention employs a shutdown protection method, but is not limited to this method; other methods include power limiting and speed limiting.

[0100] When the pitch system performs a shutdown operation using the power limiting method, the power setpoint is set to 50%-80% of the rated power, and the pitch control circuit and torque control circuit operate with limited power according to this power setpoint.

[0101] When the pitch system performs a shutdown operation using the speed-limited method, the speed setpoint is set to 70%-90% of the rated speed, and the pitch control loop operates at the speed-limited value according to this speed setpoint.

[0102] This invention also discloses a system for identifying failures in the pitch control requirements of wind turbine generator sets, specifically including:

[0103] The acquisition module is used to acquire the first input parameter, the second input parameter, the small pitch angle overspeed speed hold-up threshold, and the blade pitch requirement command;

[0104] The preprocessing module is used to preprocess the second input parameter to obtain the comparison threshold;

[0105] The first comparison module is used to compare the first input parameter with the comparison threshold;

[0106] If the first input parameter is less than or equal to the comparison threshold, the control flow ends.

[0107] If the first input parameter is greater than the comparison threshold, then the second comparison module is activated;

[0108] The calculation module is used to obtain the average angle of the current pitch requirement based on the blade pitch requirement command.

[0109] The second comparison module is used to determine the magnitude of the small pitch angle overspeed speed pitch angle threshold and the average angle of the current pitch requirement.

[0110] If the small pitch angle overspeed speed pitch angle threshold is greater than the current average pitch angle requirement, then the time accumulation module is activated.

[0111] The time accumulation module is used to accumulate time and obtain the accumulated time value;

[0112] The third comparison module is used to determine whether the cumulative time value is greater than the threshold for holding the speed overspeed time at small pitch angle.

[0113] If the cumulative time value is less than or equal to the threshold value for holding the overspeed speed at the small pitch angle, the control process terminates.

[0114] If the cumulative time value is greater than the threshold value for holding the speed overspeed at the small pitch angle, it indicates that the pitch control requirement of the wind turbine generator set has failed, and the pitch system will perform a protection operation.

[0115] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for identifying the failure of pitch control requirements in a wind turbine generator set, characterized by comprising the following steps: S1. Obtain the first input parameter and the second input parameter; The comparison threshold is obtained by preprocessing the second input parameter. If the first input parameter is less than or equal to the comparison threshold, the control flow ends. If the first input parameter is greater than the comparison threshold, start S2; S2. Obtain the small pitch angle overspeed speed pitch angle threshold and the blade pitch requirement command; The average angle of the current pitch requirement is obtained based on the blade pitch requirement command. If the small pitch angle overspeed speed pitch angle threshold is greater than the current average pitch angle requirement, then time accumulation begins to obtain the second accumulated time value. S3. Obtain the threshold for holding the speed overrun time at small pitch angle; Determine whether the second time cumulative value is greater than the small pitch angle overspeed rotational speed time hold threshold; If the cumulative value of the second time is less than or equal to the threshold value for holding the speed overspeed at the small pitch angle, the control process terminates. If the cumulative value of the second time is greater than the threshold for holding the speed overspeed at the small pitch angle, it indicates that the pitch control requirement of the wind turbine generator set has failed, and the pitch system will perform a protection operation. When the first input parameter is the generator speed, the second input parameter is the current rated speed of the generator; S1 specifically refers to: 1.

1. Obtain the current generator speed and the current rated generator speed; 1.2 Multiply the current generator rated speed by the small pitch angle overspeed gain coefficient to obtain the small pitch angle overspeed judgment value omega_rated*factor_spo; 1.

3. Determine whether the current generator speed is greater than the overspeed judgment value omega_rated*factor_spo for small pitch angle; If the current generator speed is less than or equal to the small pitch angle overspeed judgment value omega_rated*factor_spo, the control process ends; If the current generator speed is greater than the small pitch angle overspeed judgment value omega_rated*factor_spo, time accumulation begins to obtain the first accumulated time value; When the obtained blade pitch demand command is a three-blade pitch demand command, in S2, the current pitch demand angle of the three blades is averaged to obtain the average current pitch demand angle of the three blades. Determine whether the average angle of the current pitch requirement of the three blades is less than the small pitch angle overspeed speed pitch angle threshold. If the pitch angle threshold is less than or equal to the average angle of the current pitch requirement of the three blades, the control process will terminate. If the small pitch angle overspeed speed pitch angle threshold is greater than the average angle of the current pitch requirement of the three blades, time accumulation begins to obtain the second time accumulation value. In S3, the pitch system performs protection operations in the form of shutdown, power limiting, or speed limiting.

2. The method for identifying the failure of pitch control requirements in a wind turbine generator set according to claim 1, characterized in that, The average pitch angle required by the three blades is obtained by averaging the current pitch angles of the three blades. The specific process is as follows: The summation of the current pitch demand angles of the three blades is expressed as: pitch_demand_sum = pitch_demand1 + pitch_demand2 + pitch_demand3; Where 1 pitch_demand1 is the current pitch demand angle of the first blade; pitch_demand2 is the current pitch demand angle of the second blade; and 3 pitch_demand3 is the current pitch demand angle of the third blade. Divide pitch_demand_sum by 3 to get the average pitch demand angle for the three-bladed pitch.

3. The method for identifying the failure of pitch control requirements in a wind turbine generator set according to claim 1, characterized in that, When the pitch system performs a shutdown operation using the shutdown method, the specific steps are as follows: The pitch control system retracts the pitch to its final position according to the pitch rate requirement, and the generator torque is given by looking up the generator speed in a table.

4. The method for identifying the failure of pitch control requirements in a wind turbine generator set according to claim 1, characterized in that, When the pitch system performs a shutdown operation using the power limiting method, the power setpoint is set to 50%-80% of the rated power, and the pitch control circuit and torque control circuit operate with limited power according to this power setpoint.

5. The method for identifying the failure of pitch control requirements in a wind turbine generator set according to claim 1, characterized in that, When the pitch system performs a shutdown operation using the speed-limited method, the speed setpoint is set to 70%-90% of the rated speed, and the pitch control loop operates at the speed-limited value according to this speed setpoint.

6. A system for identifying failures in the pitch control requirements of a wind turbine generator set, characterized in that, Specifically, it includes: The acquisition module is used to acquire the first input parameter, the second input parameter, the small pitch angle overspeed speed hold-up threshold, and the blade pitch requirement command; The preprocessing module is used to preprocess the second input parameter to obtain the comparison threshold; The first comparison module is used to compare the first input parameter with the comparison threshold; If the first input parameter is less than or equal to the comparison threshold, the control flow ends. If the first input parameter is greater than the comparison threshold, then the second comparison module is activated; The calculation module is used to obtain the average angle of the current pitch requirement based on the blade pitch requirement command. The second comparison module is used to determine the magnitude of the small pitch angle overspeed speed pitch angle threshold and the average angle of the current pitch requirement. If the small pitch angle overspeed speed pitch angle threshold is greater than the current average pitch angle requirement, then the time accumulation module is activated. The time accumulation module is used to accumulate time and obtain the accumulated time value; The third comparison module is used to determine whether the cumulative time value is greater than the threshold for holding the speed overspeed time at small pitch angle. If the cumulative time value is less than or equal to the threshold value for holding the overspeed speed at the small pitch angle, the control process terminates. If the cumulative time value is greater than the threshold value for holding the speed overspeed at the small pitch angle, it indicates that the pitch control requirement of the wind turbine generator set has failed, and the pitch system will perform a protection operation.

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